1. Field of the Invention
The present disclosure relates to a semiconductor substrate.
The present disclosure also relates to a manufacturing method of a semiconductor substrate.
2. Description of the Related Art
A variety of electronic devices using a compound semiconductor material are being developed.
Examples of electronic devices may include a solar cell, a photodetector, or a light-emitting device.
Such electronic devices may have various defects due to a difference in lattice constant, thermal expansion coefficient, or strain between a growth substrate and a compound semiconductor layer formed thereon.
The difference in lattice constant between a growth substrate and a compound semiconductor layer causes a defect such as dislocation in the compound semiconductor layer, resulting in deterioration of the crystallinity of the compound semiconductor layer and thus degrading electrical or optical characteristics of an electronic device.
In addition, the differences in lattice constant and thermal expansion coefficient between the growth substrate and the compound semiconductor layer cause a strain therebetween. That is, an unbalance between a compressive strain upon growth of compound semiconductors and a tensile strain upon cooling down to the room temperature after the growth results in cracks in the compound semiconductor layer or causes the growth substrate to be broken.
Since the cracks occur in the compound semiconductor layer, there is a limitation in that a conductive semiconductor layer that substantially functions as a solar cell, a photodetector, or light emitting device is grown to a great thickness.
In order to overcome this limitation, a low-temperature AlN layer is provided, which is grown between the growth substrate and the compound semiconductor layer at low temperature of 800° C. to 900° C. and formed in a single layer. However, although the low-temperature AlN layer is provided, the crystallinity or stain of the compound semiconductor layer is not yet sufficiently controlled.